The AJCC (American Joint Committee on Cancer) and UICC (International Union Against Cancer) have chosen staging by TNM (Tumor-Node-Metastasis) classification to define cancer (TNM Classification of Malignant Tumours 7th edition, ISBN: 978-1-4443-3241-4, December 2009), hereinafter referred to as Ref. 1. The TNM system describes how to classify the extent of cancer based on morphological attributes of malignant tumors which are thought to influence disease prognosis (e.g. the size of the primary tumor or distance of the tumor to other structures). To stage a tumor, clinicians, e.g., physicians, are required to measure the greatest dimension of a tumor (see FIG. 1) and, subsequently, apply TNM staging rules to classify the tumor (see Table 1). This is prone to error, time consuming and inconvenient.